Code execution request routing

ABSTRACT

A system for providing low-latency compute capacity is provided. The system may be configured to route incoming code execution requests based on user indications to use specific containers running on a plurality of virtual machine instances. The system may be configured to process a code execution request, identify, based on the user indication that a specific container previously used to handle a request of similar type is to be used for handling the code execution request, and cause the code execution request to be handled using the specific container.

BACKGROUND

Generally described, computing devices utilize a communication network,or a series of communication networks, to exchange data. Companies andorganizations operate computer networks that interconnect a number ofcomputing devices to support operations or provide services to thirdparties. The computing systems can be located in a single geographiclocation or located in multiple, distinct geographic locations (e.g.,interconnected via private or public communication networks).Specifically, data centers or data processing centers, herein generallyreferred to as a “data center,” may include a number of interconnectedcomputing systems to provide computing resources to users of the datacenter. The data centers may be private data centers operated on behalfof an organization or public data centers operated on behalf, or for thebenefit of, the general public.

To facilitate increased utilization of data center resources,virtualization technologies may allow a single physical computing deviceto host one or more instances of virtual machines that appear andoperate as independent computing devices to users of a data center. Withvirtualization, the single physical computing device can create,maintain, delete, or otherwise manage virtual machines in a dynamicmanner. In turn, users can request computer resources from a datacenter, including single computing devices or a configuration ofnetworked computing devices, and be provided with varying numbers ofvirtual machine resources.

In some scenarios, virtual machine instances may be configured accordingto a number of virtual machine instance types to provide specificfunctionality. For example, various computing devices may be associatedwith different combinations of operating systems or operating systemconfigurations, virtualized hardware resources and software applicationsto enable a computing device to provide different desiredfunctionalities, or to provide similar functionalities more efficiently.These virtual machine instance type configurations are often containedwithin a device image, which includes static data containing thesoftware (e.g., the OS and applications together with theirconfiguration and data files, etc.) that the virtual machine will runonce started. The device image is typically stored on the disk used tocreate or initialize the instance. Thus, a computing device may processthe device image in order to implement the desired softwareconfiguration.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing aspects and many of the attendant advantages of thisdisclosure will become more readily appreciated as the same becomebetter understood by reference to the following detailed description,when taken in conjunction with the accompanying drawings, wherein:

FIG. 1 is a block diagram depicting an illustrative environment forproviding low latency compute capacity, according to an example aspect;

FIG. 2 depicts a general architecture of a computing device providing arouting manager for routing code execution requests, according to anexample aspect;

FIG. 3 is a flow diagram illustrating a code execution request routingroutine implemented by a routing manager, according to an exampleaspect;

FIG. 4 depicts an example mapping table illustrating the routing ofrequests to containers, according to an example aspect;

FIG. 5 is a flow diagram illustrating a code execution result cachingroutine implemented by a routing manager, according to an exampleaspect; and

FIG. 6 is a flow diagram illustrating a container lifecycle managementroutine implemented by a routing manager, according to an exampleaspect.

DETAILED DESCRIPTION

Companies and organizations no longer need to acquire and manage theirown data centers in order to perform computing operations (e.g., executecode, including threads, programs, functions, software, routines,subroutines, processes, etc.). With the advent of cloud computing,storage space and compute power traditionally provided by hardwarecomputing devices can now be obtained and configured in minutes over theInternet. Thus, developers can quickly purchase a desired amount ofcomputing resources without having to worry about acquiring physicalmachines. Such computing resources are typically purchased in the formof virtual computing resources, or virtual machine instances. Theseinstances of virtual machines are software implementations of physicalmachines (e.g., computers), which are hosted on physical computingdevices, and may contain operating systems and applications that aretraditionally provided on physical machines. These virtual machineinstances are configured with a set of computing resources (e.g.,memory, CPU, disk, network, etc.) that applications running on thevirtual machine instances may request and can be utilized in the samemanner as physical computers.

However, even when virtual computing resources are purchased, developersstill have to decide how many and what type of virtual machine instancesto purchase, and how long to keep them. For example, the costs of usingthe virtual machine instances may vary depending on the type and thenumber of hours they are rented. In addition, the minimum time a virtualmachine may be rented is typically on the order of hours. Further,developers have to specify the hardware and software resources (e.g.,type of operating systems and language runtimes, etc.) to install on thevirtual machines. Other concerns that they might have includeover-utilization (e.g., acquiring too little computing resources andsuffering performance issues), under-utilization (e.g., acquiring morecomputing resources than necessary to run the codes, and thusoverpaying), prediction of change in traffic (e.g., so that they knowwhen to scale up or down), and instance and language runtime startupdelay, which can take 3-10 minutes, or longer, even though users maydesire computing capacity on the order of seconds or even milliseconds.

According to aspects of the present disclosure, by maintaining a pool ofpre-initialized virtual machine instances that are ready for use as soonas a user request is received, and automatically managing the amount ofcapacity available in the pool to service incoming requests, delay(sometimes referred to as latency) associated with executing the usercode (e.g., instance and language runtime startup time) can besignificantly reduced, and utilization can be improved.

Generally described, systems and methods are disclosed which facilitatemanagement of virtual machine instances in a virtual compute system. Thevirtual compute system maintains a pool of virtual machine instancesthat have one or more software components (e.g., operating systems,language runtimes, libraries, etc.) loaded thereon. Maintaining the poolof virtual machine instances may involve creating a new instance,acquiring a new instance from an external instance provisioning service,destroying an instance, assigning/reassigning an instance to a user,modifying an instance (e.g., containers or resources therein), etc. Thevirtual machine instances in the pool can be designated to service userrequests to execute program codes. In the present disclosure, thephrases “program code,” “user code,” and “cloud function” may sometimesbe interchangeably used. The program codes can be executed in isolatedcontainers that are created on the virtual machine instances. Since thevirtual machine instances in the pool have already been booted andloaded with particular operating systems and language runtimes by thetime the requests are received, the delay associated with findingcompute capacity that can handle the requests (e.g., by executing theuser code in one or more containers created on the virtual machineinstances) is significantly reduced.

In another aspect, a virtual compute system may create and manage amapping between incoming code execution requests received by the virtualcompute system and the compute capacity used to handle those codeexecution requests. The mapping may facilitate use and reuse of certaincontainer-specific resources by multiple requests. For example, a givencontainer may be associated with a cache that stores code executionresults and may be accessed by any program code executed in the givencontainer. Accordingly, once the code execution result associated with arequest is stored in the cache, subsequent requests of the same type, ifrouted to the given container, may be handled more efficiently using thecode execution results stored in the cache. Thus, by routing therequests to the appropriate containers running on the virtual computesystem, latency gains may be achieved.

Specific embodiments and example applications of the present disclosurewill now be described with reference to the drawings. These embodimentsand example applications are intended to illustrate, and not limit, thepresent disclosure.

Illustrative Environment Including Virtual Compute System

With reference to FIG. 1, a block diagram illustrating an embodiment ofa virtual environment 100 will be described. The example shown in FIG. 1includes a virtual environment 100 in which users (e.g., developers,etc.) of user computing devices 102 may run various program codes usingthe virtual computing resources provided by a virtual compute system110.

By way of illustration, various example user computing devices 102 areshown in communication with the virtual compute system 110, including adesktop computer, laptop, and a mobile phone. In general, the usercomputing devices 102 can be any computing device such as a desktop,laptop, mobile phone (or smartphone), tablet, kiosk, wireless device,and other electronic devices. In addition, the user computing devices102 may include web services running on the same or different datacenters, where, for example, different web services may programmaticallycommunicate with each other to perform one or more techniques describedherein. Further, the user computing devices 102 may include Internet ofThings (IoT) devices such as Internet appliances and connected devices.The virtual compute system 110 may provide the user computing devices102 with one or more user interfaces, command-line interfaces (CLI),application programming interfaces (API), and/or other programmaticinterfaces for generating and uploading user codes, invoking the usercodes (e.g., submitting a request to execute the user codes on thevirtual compute system 110), scheduling event-based jobs or timed jobs,tracking the user codes, and/or viewing other logging or monitoringinformation related to their requests and/or user codes. Although one ormore embodiments may be described herein as using a user interface, itshould be appreciated that such embodiments may, additionally oralternatively, use any CLIs, APIs, or other programmatic interfaces.

The user computing devices 102 access the virtual compute system 110over a network 104. The network 104 may be any wired network, wirelessnetwork, or combination thereof. In addition, the network 104 may be apersonal area network, local area network, wide area network,over-the-air broadcast network (e.g., for radio or television), cablenetwork, satellite network, cellular telephone network, or combinationthereof. For example, the network 104 may be a publicly accessiblenetwork of linked networks, possibly operated by various distinctparties, such as the Internet. In some embodiments, the network 104 maybe a private or semi-private network, such as a corporate or universityintranet. The network 104 may include one or more wireless networks,such as a Global System for Mobile Communications (GSM) network, a CodeDivision Multiple Access (CDMA) network, a Long Term Evolution (LTE)network, or any other type of wireless network. The network 104 can useprotocols and components for communicating via the Internet or any ofthe other aforementioned types of networks. For example, the protocolsused by the network 104 may include Hypertext Transfer Protocol (HTTP),HTTP Secure (HTTPS), Message Queue Telemetry Transport (MQTT),Constrained Application Protocol (CoAP), and the like. Protocols andcomponents for communicating via the Internet or any of the otheraforementioned types of communication networks are well known to thoseskilled in the art and, thus, are not described in more detail herein.

The virtual compute system 110 is depicted in FIG. 1 as operating in adistributed computing environment including several computer systemsthat are interconnected using one or more computer networks. The virtualcompute system 110 could also operate within a computing environmenthaving a fewer or greater number of devices than are illustrated inFIG. 1. Thus, the depiction of the virtual compute system 110 in FIG. 1should be taken as illustrative and not limiting to the presentdisclosure. For example, the virtual compute system 110 or variousconstituents thereof could implement various Web services components,hosted or “cloud” computing environments, and/or peer-to-peer networkconfigurations to implement at least a portion of the processesdescribed herein.

Further, the virtual compute system 110 may be implemented in hardwareand/or software and may, for instance, include one or more physical orvirtual servers implemented on physical computer hardware configured toexecute computer executable instructions for performing various featuresthat will be described herein. The one or more servers may begeographically dispersed or geographically co-located, for instance, inone or more data centers.

In the environment illustrated FIG. 1, the virtual environment 100includes a virtual compute system 110, which includes a frontend 120, awarming pool manager 130, a worker manager 140, and a routing manager150. In the depicted example, virtual machine instances (“instances”)152, 154 are shown in a warming pool 130A managed by the warming poolmanager 130, and instances 156, 157, 158, 159 are shown in an activepool 140A managed by the worker manager 140. In some embodiments, theterm “virtual machine instance” may refer to an execution of software orother executable code that emulates hardware to provide an environmentor platform on which software may execute (an “execution environment”).Virtual machine instances are generally executed by physical hardwaredevices, which may differ from the hardware emulated by the virtualmachine instance. For example, a virtual machine may emulate a firsttype of processor and memory while being executed on a second type ofprocessor and memory. Thus, virtual machines can be utilized to executesoftware intended for a first execution environment (e.g., a firstoperating system) on a physical device that is executing a secondexecution environment (e.g., a second operating system). In someinstances, hardware emulated by a virtual machine instance may be thesame or similar to hardware of an underlying device. For example, adevice with a first type of processor may implement a plurality ofvirtual machine instances, each emulating an instance of that first typeof processor. Thus, virtual machine instances can be used to divide asingle device into a number of logical sub-devices (each referred to asa “virtual machine instance”). While virtual machine instances cangenerally provide a level of abstraction away from the hardware of anunderlying physical device, this abstraction is not required. Forexample, assume a device implements a plurality of virtual machineinstances, each of which emulate hardware identical to that provided bythe device. Under such a scenario, each virtual machine instance mayallow a software application to execute code on the underlying hardwarewithout translation, while maintaining a logical separation betweensoftware applications running on other virtual machine instances. Thisprocess, which is generally referred to as “native execution,” may beutilized to increase the speed or performance of virtual machineinstances. Other techniques that allow direct utilization of underlyinghardware, such as hardware pass-through techniques, are known within theart.

The illustration of the various components within the virtual computesystem 110 is logical in nature and one or more of the components can beimplemented by a single computing device or multiple computing devices.For example, the instances 152, 154, 156, 157, 158, 159 can beimplemented on one or more physical computing devices in differentvarious geographic regions. Similarly, each of the frontend 120, thewarming pool manager 130, the worker manager 140, and the routingmanager 150 can be implemented across multiple physical computingdevices. Alternatively, one or more of the frontend 120, the warmingpool manager 130, the worker manager 140, and the routing manager 150can be implemented on a single physical computing device. In someembodiments, the virtual compute system 110 may comprise multiplefrontends, multiple warming pool managers, multiple worker managers,and/or multiple capacity managers. Although six virtual machineinstances are shown in the example of FIG. 1, the embodiments describedherein are not limited as such, and one skilled in the art willappreciate that the virtual compute system 110 may comprise any numberof virtual machine instances implemented using any number of physicalcomputing devices. Similarly, although a single warming pool and asingle active pool are shown in the example of FIG. 1, the embodimentsdescribed herein are not limited as such, and one skilled in the artwill appreciate that the virtual compute system 110 may comprise anynumber of warming pools and active pools.

In the example of FIG. 1, the virtual compute system 110 is illustratedas being connected to the network 104. In some embodiments, any of thecomponents within the virtual compute system 110 can communicate withother components (e.g., the user computing devices 102 and auxiliaryservices 106, which may include monitoring/logging/billing services 107,storage service 108, an instance provisioning service 109, and/or otherservices that may communicate with the virtual compute system 110) ofthe virtual environment 100 via the network 104. In other embodiments,not all components of the virtual compute system 110 are capable ofcommunicating with other components of the virtual environment 100. Inone example, only the frontend 120 may be connected to the network 104,and other components of the virtual compute system 110 may communicatewith other components of the virtual environment 100 via the frontend120.

Users may use the virtual compute system 110 to execute user codethereon. For example, a user may wish to run a piece of code inconnection with a web or mobile application that the user has developed.One way of running the code would be to acquire virtual machineinstances from service providers who provide infrastructure as aservice, configure the virtual machine instances to suit the user'sneeds, and use the configured virtual machine instances to run the code.Alternatively, the user may send a code execution request to the virtualcompute system 110. The virtual compute system 110 can handle theacquisition and configuration of compute capacity (e.g., containers,instances, etc., which are described in greater detail below) based onthe code execution request, and execute the code using the computecapacity. The virtual compute system 110 may automatically scale up anddown based on the volume, thereby relieving the user from the burden ofhaving to worry about over-utilization (e.g., acquiring too littlecomputing resources and suffering performance issues) orunder-utilization (e.g., acquiring more computing resources thannecessary to run the codes, and thus overpaying).

Frontend

The frontend 120 processes all the requests to execute user code on thevirtual compute system 110. In one embodiment, the frontend 120 servesas a front door to all the other services provided by the virtualcompute system 110. The frontend 120 processes the requests and makessure that the requests are properly authorized. For example, thefrontend 120 may determine whether the user associated with the requestis authorized to access the user code specified in the request.

The user code as used herein may refer to any program code (e.g., aprogram, routine, subroutine, thread, etc.) written in a specificprogram language. In the present disclosure, the terms “code,” “usercode,” and “program code,” may be used interchangeably. Such user codemay be executed to achieve a specific task, for example, in connectionwith a particular web application or mobile application developed by theuser. For example, the user codes may be written in JavaScript(node.js), Java, Python, and/or Ruby. The request may include the usercode (or the location thereof) and one or more arguments to be used forexecuting the user code. For example, the user may provide the user codealong with the request to execute the user code. In another example, therequest may identify a previously uploaded program code (e.g., using theAPI for uploading the code) by its name or its unique ID. In yet anotherexample, the code may be included in the request as well as uploaded ina separate location (e.g., the storage service 108 or a storage systeminternal to the virtual compute system 110) prior to the request isreceived by the virtual compute system 110. The virtual compute system110 may vary its code execution strategy based on where the code isavailable at the time the request is processed.

The frontend 120 may receive the request to execute such user codes inresponse to Hypertext Transfer Protocol Secure (HTTPS) requests from auser. Also, any information (e.g., headers and parameters) included inthe HTTPS request may also be processed and utilized when executing theuser code. As discussed above, any other protocols, including, forexample, HTTP, MQTT, and CoAP, may be used to transfer the messagecontaining the code execution request to the frontend 120. The frontend120 may also receive the request to execute such user codes when anevent is detected, such as an event that the user has registered totrigger automatic request generation. For example, the user may haveregistered the user code with an auxiliary service 106 and specifiedthat whenever a particular event occurs (e.g., a new file is uploaded),the request to execute the user code is sent to the frontend 120.Alternatively, the user may have registered a timed job (e.g., executethe user code every 24 hours). In such an example, when the scheduledtime arrives for the timed job, the request to execute the user code maybe sent to the frontend 120. In yet another example, the frontend 120may have a queue of incoming code execution requests, and when theuser's batch job is removed from the virtual compute system's workqueue, the frontend 120 may process the user request. In yet anotherexample, the request may originate from another component within thevirtual compute system 110 or other servers or services not illustratedin FIG. 1.

A user request may specify one or more third-party libraries (includingnative libraries) to be used along with the user code. In oneembodiment, the user request is a ZIP file containing the user code andany libraries (and/or identifications of storage locations thereof). Insome embodiments, the user request includes metadata that indicates theprogram code to be executed, the language in which the program code iswritten, the user associated with the request, and/or the computingresources (e.g., memory, etc.) to be reserved for executing the programcode. For example, the program code may be provided with the request,previously uploaded by the user, provided by the virtual compute system110 (e.g., standard routines), and/or provided by third parties. In someembodiments, such resource-level constraints (e.g., how much memory isto be allocated for executing a particular user code) are specified forthe particular user code, and may not vary over each execution of theuser code. In such cases, the virtual compute system 110 may have accessto such resource-level constraints before each individual request isreceived, and the individual requests may not specify suchresource-level constraints. In some embodiments, the user request mayspecify other constraints such as permission data that indicates whatkind of permissions that the request has to execute the user code. Suchpermission data may be used by the virtual compute system 110 to accessprivate resources (e.g., on a private network).

In some embodiments, the user request may specify the behavior thatshould be adopted for handling the user request. In such embodiments,the user request may include an indicator for enabling one or moreexecution modes in which the user code associated with the user requestis to be executed. For example, the request may include a flag or aheader for indicating whether the user code should be executed in adebug mode in which the debugging and/or logging output that may begenerated in connection with the execution of the user code is providedback to the user (e.g., via a console user interface). In such anexample, the virtual compute system 110 may inspect the request and lookfor the flag or the header, and if it is present, the virtual computesystem 110 may modify the behavior (e.g., logging facilities) of thecontainer in which the user code is executed, and cause the output datato be provided back to the user. In some embodiments, the behavior/modeindicators are added to the request by the user interface provided tothe user by the virtual compute system 110. Other features such assource code profiling, remote debugging, etc. may also be enabled ordisabled based on the indication provided in the request.

In some embodiments, the virtual compute system 110 may include multiplefrontends 120. In such embodiments, a load balancer may be provided todistribute the incoming requests to the multiple frontends 120, forexample, in a round-robin fashion. In some embodiments, the manner inwhich the load balancer distributes incoming requests to the multiplefrontends 120 may be based on the state of the warming pool 130A and/orthe active pool 140A. For example, if the capacity in the warming pool130A is deemed to be sufficient, the requests may be distributed to themultiple frontends 120 based on the individual capacities of thefrontends 120 (e.g., based on one or more load balancing restrictions).On the other hand, if the capacity in the warming pool 130A is less thana threshold amount, one or more of such load balancing restrictions maybe removed such that the requests may be distributed to the multiplefrontends 120 in a manner that reduces or minimizes the number ofvirtual machine instances taken from the warming pool 130A. For example,even if, according to a load balancing restriction, a request is to berouted to Frontend A, if Frontend A needs to take an instance out of thewarming pool 130A to service the request but Frontend B can use one ofthe instances in its active pool to service the same request, therequest may be routed to Frontend B.

Warming Pool Manager

The warming pool manager 130 ensures that virtual machine instances areready to be used by the worker manager 140 when the virtual computesystem 110 receives a request to execute user code on the virtualcompute system 110. In the example illustrated in FIG. 1, the warmingpool manager 130 manages the warming pool 130A, which is a group(sometimes referred to as a pool) of pre-initialized and pre-configuredvirtual machine instances that may be used to service incoming user codeexecution requests. In some embodiments, the warming pool manager 130causes virtual machine instances to be booted up on one or more physicalcomputing machines within the virtual compute system 110 and added tothe warming pool 130A. In other embodiments, the warming pool manager130 communicates with an auxiliary virtual machine instance service(e.g., the instance provisioning service 109 of FIG. 1) to create andadd new instances to the warming pool 130A. In some embodiments, thewarming pool manager 130 may utilize both physical computing deviceswithin the virtual compute system 110 and one or more virtual machineinstance services to acquire and maintain compute capacity that can beused to service code execution requests received by the frontend 120. Insome embodiments, the virtual compute system 110 may comprise one ormore logical knobs or switches for controlling (e.g., increasing ordecreasing) the available capacity in the warming pool 130A. Forexample, a system administrator may use such a knob or switch toincrease the capacity available (e.g., the number of pre-bootedinstances) in the warming pool 130A during peak hours. In someembodiments, virtual machine instances in the warming pool 130A can beconfigured based on a predetermined set of configurations independentfrom a specific user request to execute a user's code. The predeterminedset of configurations can correspond to various types of virtual machineinstances to execute user codes. The warming pool manager 130 canoptimize types and numbers of virtual machine instances in the warmingpool 130A based on one or more metrics related to current or previoususer code executions.

As shown in FIG. 1, instances may have operating systems (OS) and/orlanguage runtimes loaded thereon. For example, the warming pool 130Amanaged by the warming pool manager 130 comprises instances 152, 154.The instance 152 includes an OS 152A and a runtime 152B. The instance154 includes an OS 154A. In some embodiments, the instances in thewarming pool 130A may also include containers (which may further containcopies of operating systems, runtimes, user codes, etc.), which aredescribed in greater detail below. Although the instance 152 is shown inFIG. 1 to include a single runtime, in other embodiments, the instancesdepicted in FIG. 1 may include two or more runtimes, each of which maybe used for running a different user code. In some embodiments, thewarming pool manager 130 may maintain a list of instances in the warmingpool 130A. The list of instances may further specify the configuration(e.g., OS, runtime, container, etc.) of the instances.

In some embodiments, the virtual machine instances in the warming pool130A may be used to serve any user's request. In one embodiment, all thevirtual machine instances in the warming pool 130A are configured in thesame or substantially similar manner. In another embodiment, the virtualmachine instances in the warming pool 130A may be configured differentlyto suit the needs of different users. For example, the virtual machineinstances may have different operating systems, different languageruntimes, and/or different libraries loaded thereon. In yet anotherembodiment, the virtual machine instances in the warming pool 130A maybe configured in the same or substantially similar manner (e.g., withthe same OS, language runtimes, and/or libraries), but some of thoseinstances may have different container configurations. For example, twoinstances may have runtimes for both Python and Ruby, but one instancemay have a container configured to run Python code, and the otherinstance may have a container configured to run Ruby code. In someembodiments, multiple warming pools 130A, each havingidentically-configured virtual machine instances, are provided.

The warming pool manager 130 may pre-configure the virtual machineinstances in the warming pool 130A, such that each virtual machineinstance is configured to satisfy at least one of the operatingconditions that may be requested or specified by the user request toexecute program code on the virtual compute system 110. In oneembodiment, the operating conditions may include program languages inwhich the potential user codes may be written. For example, suchlanguages may include Java, JavaScript, Python, Ruby, and the like. Insome embodiments, the set of languages that the user codes may bewritten in may be limited to a predetermined set (e.g., set of 4languages, although in some embodiments sets of more or less than fourlanguages are provided) in order to facilitate pre-initialization of thevirtual machine instances that can satisfy requests to execute usercodes. For example, when the user is configuring a request via a userinterface provided by the virtual compute system 110, the user interfacemay prompt the user to specify one of the predetermined operatingconditions for executing the user code. In another example, theservice-level agreement (SLA) for utilizing the services provided by thevirtual compute system 110 may specify a set of conditions (e.g.,programming languages, computing resources, etc.) that user requestsshould satisfy, and the virtual compute system 110 may assume that therequests satisfy the set of conditions in handling the requests. Inanother example, operating conditions specified in the request mayinclude: the amount of compute power to be used for processing therequest; the type of the request (e.g., HTTP vs. a triggered event); thetimeout for the request (e.g., threshold time after which the requestmay be terminated); security policies (e.g., may control which instancesin the warming pool 130A are usable by which user); schedulinginformation (e.g., the time by which the virtual compute system isrequested to execute the program code, the time after which the virtualcompute system is requested to execute the program code, the temporalwindow within which the virtual compute system is requested to executethe program code, etc.), etc.

Worker Manager

The worker manager 140 manages the instances used for servicing incomingcode execution requests. In the example illustrated in FIG. 1, theworker manager 140 manages the active pool 140A, which is a group(sometimes referred to as a pool) of virtual machine instances that arecurrently assigned to one or more users. Although the virtual machineinstances are described here as being assigned to a particular user, insome embodiments, the instances may be assigned to a group of users,such that the instance is tied to the group of users and any member ofthe group can utilize resources on the instance. For example, the usersin the same group may belong to the same security group (e.g., based ontheir security credentials) such that executing one member's code in acontainer on a particular instance after another member's code has beenexecuted in another container on the same instance does not posesecurity risks. Similarly, the worker manager 140 may assign theinstances and the containers according to one or more policies thatdictate which requests can be executed in which containers and whichinstances can be assigned to which users. An example policy may specifythat instances are assigned to collections of users who share the sameaccount (e.g., account for accessing the services provided by thevirtual compute system 110). In some embodiments, the requestsassociated with the same user group may share the same containers (e.g.,if the user codes associated therewith are identical). In someembodiments, a request does not differentiate between the differentusers of the group and simply indicates the group to which the usersassociated with the requests belong.

In the example illustrated in FIG. 1, user codes are executed inisolated compute systems referred to as containers. Containers arelogical units created within a virtual machine instance using theresources available on that instance. For example, the worker manager140 may, based on information specified in the request to execute usercode, create a new container or locate an existing container in one ofthe instances in the active pool 140A and assigns the container to therequest to handle the execution of the user code associated with therequest. In one embodiment, such containers are implemented as Linuxcontainers. The virtual machine instances in the active pool 140A mayhave one or more containers created thereon and have one or more programcodes associated with the user loaded thereon (e.g., either in one ofthe containers or in a local cache of the instance).

As shown in FIG. 1, instances may have operating systems (OS), languageruntimes, and containers. The containers may have individual copies ofthe OS and the language runtimes and user codes loaded thereon. In theexample of FIG. 1, the active pool 140A managed by the worker manager140 includes the instances 156, 157, 158, 159. The instance 156 hascontainers 156A, 156B. The container 156A has OS 156A-1, runtime 156A-2,and code 156A-3 loaded therein. In the depicted example, the container156A has its own OS, runtime, and code loaded therein. In oneembodiment, the OS 156A-1 (e.g., the kernel thereof), runtime 156A-2,and/or code 156A-3 are shared among the containers 156A, 156B (and anyother containers not illustrated in FIG. 1). In another embodiment, theOS 156A-1 (e.g., any code running outside the kernel), runtime 156A-2,and/or code 156A-3 are independent copies that are created for thecontainer 156A and are not shared with other containers on the instance156. In yet another embodiment, some portions of the OS 156A-1, runtime156A-2, and/or code 156A-3 are shared among the containers on theinstance 156, and other portions thereof are independent copies that arespecific to the container 156A. The instance 157 includes containers157A, 157B, 157C. The instance 158 includes containers 158A, 158B andresources 158C. The instance 159 includes a container 159A and resources159A-1. The resources 158C may be instance-specific resources such asmemory, disk storage, database, etc. that are accessible by anycontainer (or any code executed therein) created thereon. The resources159A-1 may be container-specific resources such as memory, disk storage,database, etc. that are accessible by any code executed therein.

In the example of FIG. 1, the sizes of the containers depicted in FIG. 1may be proportional to the actual size of the containers. For example,the container 156A occupies more space than the container 156B on theinstance 156. Similarly, the containers 157A, 157B, 157C may be equallysized, and the containers 158A and 158B may be equally sized. The dottedboxes labeled “C” shown in the instances 158, 159 indicate the spaceremaining on the instances that may be used to create new instances. Insome embodiments, the sizes of the containers may be 64 MB or anymultiples thereof. In other embodiments, the sizes of the containers maybe any arbitrary size smaller than or equal to the size of the instancesin which the containers are created. In some embodiments, the sizes ofthe containers may be any arbitrary size smaller than, equal to, orlarger than the size of the instances in which the containers arecreated. By how much the sizes of the containers can exceed the size ofthe instance may be determined based on how likely that those containersmight be utilized beyond the capacity provided by the instance.

Although the components inside the containers 156B, 157A, 157B, 157C,158A, 158B, 159A are not illustrated in the example of FIG. 1, each ofthese containers may have various operating systems, language runtimes,libraries, and/or user code. In some embodiments, instances may haveuser codes loaded thereon (e.g., in an instance-level cache such as theresources 158C), and containers within those instances may also haveuser codes loaded therein. In some embodiments, the worker manager 140may maintain a list of instances in the active pool 140A. The list ofinstances may further specify the configuration (e.g., OS, runtime,container, etc.) of the instances. In some embodiments, the workermanager 140 may have access to a list of instances in the warming pool130A (e.g., including the number and type of instances). In otherembodiments, the worker manager 140 requests compute capacity from thewarming pool manager 130 without having knowledge of the virtual machineinstances in the warming pool 130A.

After a request has been successfully processed by the frontend 120, theworker manager 140 finds capacity to service the request to execute usercode on the virtual compute system 110. For example, if there exists aparticular virtual machine instance in the active pool 140A that has acontainer with the same user code loaded therein (e.g., code 156A-3shown in the container 156A), the worker manager 140 may assign thecontainer to the request and cause the user code to be executed in thecontainer. Alternatively, if the user code is available in the localcache of one of the virtual machine instances (e.g., stored on theinstance 158 but does not belong to any individual containers), theworker manager 140 may create a new container on such an instance,assign the container to the request, and cause the user code to beloaded and executed in the container.

If the worker manager 140 determines that the user code associated withthe request is not found on any of the instances (e.g., either in acontainer or the local cache of an instance) in the active pool 140A,the worker manager 140 may determine whether any of the instances in theactive pool 140A is currently assigned to the user associated with therequest and has compute capacity to handle the current request. If thereis such an instance, the worker manager 140 may create a new containeron the instance and assign the container to the request. Alternatively,the worker manager 140 may further configure an existing container onthe instance assigned to the user, and assign the container to therequest. For example, the worker manager 140 may determine that theexisting container may be used to execute the user code if a particularlibrary demanded by the current user request is loaded thereon. In sucha case, the worker manager 140 may load the particular library and theuser code onto the container and use the container to execute the usercode.

If the active pool 140A does not contain any instances currentlyassigned to the user, the worker manager 140 pulls a new virtual machineinstance from the warming pool 130A, assigns the instance to the userassociated with the request, creates a new container on the instance,assigns the container to the request, and causes the user code to bedownloaded and executed on the container.

In some embodiments, the virtual compute system 110 is adapted to beginexecution of the user code shortly after it is received (e.g., by thefrontend 120). A time period can be determined as the difference in timebetween initiating execution of the user code (e.g., in a container on avirtual machine instance associated with the user) and receiving arequest to execute the user code (e.g., received by a frontend). Thevirtual compute system 110 is adapted to begin execution of the usercode within a time period that is less than a predetermined duration. Inone embodiment, the predetermined duration is 500 ms. In anotherembodiment, the predetermined duration is 300 ms. In another embodiment,the predetermined duration is 100 ms. In another embodiment, thepredetermined duration is 50 ms. In another embodiment, thepredetermined duration is 10 ms. In another embodiment, thepredetermined duration may be any value chosen from the range of 10 msto 500 ms. In some embodiments, the virtual compute system 110 isadapted to begin execution of the user code within a time period that isless than a predetermined duration if one or more conditions aresatisfied. For example, the one or more conditions may include any oneof: (1) the user code is loaded on a container in the active pool 140Aat the time the request is received; (2) the user code is stored in thecode cache of an instance in the active pool 140A at the time therequest is received; (3) the active pool 140A contains an instanceassigned to the user associated with the request at the time the requestis received; or (4) the warming pool 130A has capacity to handle therequest at the time the request is received. In some embodiments,instead of initiating the requested code execution as soon as the codeexecution request is received, the virtual compute system 110 mayschedule the code execution according to the scheduling informationprovided by the request. For example, the request may specify a temporalwindow (e.g., between 3:00 AM to 4:00 AM next Monday) within which thevirtual compute system 110 is requested to perform the code execution,and the virtual compute system 110 may schedule the code execution basedon certain performance considerations (e.g., workload, latency, etc.).

The user code may be downloaded from an auxiliary service 106 such asthe storage service 108 of FIG. 1. Data 108A illustrated in FIG. 1 maycomprise user codes uploaded by one or more users, metadata associatedwith such user codes, or any other data utilized by the virtual computesystem 110 to perform one or more techniques described herein. Althoughonly the storage service 108 is illustrated in the example of FIG. 1,the virtual environment 100 may include other levels of storage systemsfrom which the user code may be downloaded. For example, each instancemay have one or more storage systems either physically (e.g., a localstorage resident on the physical computing system on which the instanceis running) or logically (e.g., a network-attached storage system innetwork communication with the instance and provided within or outsideof the virtual compute system 110) associated with the instance on whichthe container is created. Alternatively, the code may be downloaded froma web-based data store provided by the storage service 108.

Once the worker manager 140 locates one of the virtual machine instancesin the warming pool 130A that can be used to serve the user codeexecution request, the warming pool manager 130 or the worker manager140 takes the instance out of the warming pool 130A and assigns it tothe user associated with the request. The assigned virtual machineinstance is taken out of the warming pool 130A and placed in the activepool 140A. In some embodiments, once the virtual machine instance hasbeen assigned to a particular user, the same virtual machine instancecannot be used to service requests of any other user. This providessecurity benefits to users by preventing possible co-mingling of userresources. Alternatively, in some embodiments, multiple containersbelonging to different users (or assigned to requests associated withdifferent users) may co-exist on a single virtual machine instance. Suchan approach may improve utilization of the available compute capacity.In some embodiments, the virtual compute system 110 may maintain aseparate cache in which user codes are stored to serve as anintermediate level of caching system between the local cache of thevirtual machine instances and a web-based network storage (e.g.,accessible via the network 104).

After the user code has been executed, the worker manager 140 may teardown the container used to execute the user code to free up theresources it occupied to be used for other containers in the instance.Alternatively, the worker manager 140 may keep the container running touse it to service additional requests from the same user. For example,if another request associated with the same user code that has alreadybeen loaded in the container is received, the request can be assigned tothe same container, thereby eliminating the delay associated withcreating a new container and loading the user code in the container. Insome embodiments, the worker manager 140 may tear down the instance inwhich the container used to execute the user code was created.Alternatively, the worker manager 140 may keep the instance running touse it to service additional requests from the same user. Thedetermination of whether to keep the container and/or the instancerunning after the user code is done executing may be based on athreshold time, the type of the user, average request volume of theuser, periodicity information (e.g., containers/instances in the activepool 140A not currently executing user code thereon can be (i) keptalive if the periodicity information indicates that additional requestsare expected to arrive soon or (ii) terminated if the periodicityinformation indicates that additional requests are not likely to arrivesoon enough to justify keeping the containers/instances alive), and/orother operating conditions. For example, after a threshold time haspassed (e.g., 5 minutes, 30 minutes, 1 hour, 24 hours, 30 days, etc.)without any activity (e.g., running of the code), the container and/orthe virtual machine instance is shutdown (e.g., deleted, terminated,etc.), and resources allocated thereto are released. In someembodiments, the threshold time passed before a container is torn downis shorter than the threshold time passed before an instance is torndown.

In some embodiments, the virtual compute system 110 may provide data toone or more of the auxiliary services 106 as it services incoming codeexecution requests. For example, the virtual compute system 110 maycommunicate with the monitoring/logging/billing services 107. Themonitoring/logging/billing services 107 may include: a monitoringservice for managing monitoring information received from the virtualcompute system 110, such as statuses of containers and instances on thevirtual compute system 110; a logging service for managing logginginformation received from the virtual compute system 110, such asactivities performed by containers and instances on the virtual computesystem 110; and a billing service for generating billing informationassociated with executing user code on the virtual compute system 110(e.g., based on the monitoring information and/or the logginginformation managed by the monitoring service and the logging service).In addition to the system-level activities that may be performed by themonitoring/logging/billing services 107 (e.g., on behalf of the virtualcompute system 110) as described above, the monitoring/logging/billingservices 107 may provide application-level services on behalf of theuser code executed on the virtual compute system 110. For example, themonitoring/logging/billing services 107 may monitor and/or log variousinputs, outputs, or other data and parameters on behalf of the user codebeing executed on the virtual compute system 110. Although shown as asingle block, the monitoring, logging, and billing services 107 may beprovided as separate services.

In some embodiments, the worker manager 140 may perform health checks onthe instances and containers managed by the worker manager 140 (e.g.,those in the active pool 140A). For example, the health checks performedby the worker manager 140 may include determining whether the instancesand the containers managed by the worker manager 140 have any issues of(1) misconfigured networking and/or startup configuration, (2) exhaustedmemory, (3) corrupted file system, (4) incompatible kernel, and/or anyother problems that may impair the performance of the instances and thecontainers. In one embodiment, the worker manager 140 performs thehealth checks periodically (e.g., every 5 minutes, every 30 minutes,every hour, every 24 hours, etc.). In some embodiments, the frequency ofthe health checks may be adjusted automatically based on the result ofthe health checks. In other embodiments, the frequency of the healthchecks may be adjusted based on user requests. In some embodiments, theworker manager 140 may perform similar health checks on the instancesand/or containers in the warming pool 130A. The instances and/or thecontainers in the warming pool 130A may be managed either together withthose instances and containers in the active pool 140A or separately. Insome embodiments, in the case where the health of the instances and/orthe containers in the warming pool 130A is managed separately from theactive pool 140A, the warming pool manager 130, instead of the workermanager 140, may perform the health checks described above on theinstances and/or the containers in the warming pool 130A.

Routing Manager

The routing manager 150 creates and manages a mapping between incomingcode execution requests received by the virtual compute system 110 andthe compute capacity used to handle those code execution requests. Themapping may facilitate use and reuse of certain container-specificresources by multiple requests. For example, a given container may beassociated with a cache that stores code execution results and may beaccessed by any program code executed in the given container.Accordingly, once the code execution result associated with a request isstored in the cache, subsequent requests of the same type, if routed tothe given container, may be handled more efficiently using the codeexecution results stored in the cache. Although the routing manager 150is illustrated as a distinct component within the virtual compute system110, part or all of the functionalities of the routing manager 150 maybe performed by the frontend 120, the warming pool manager 130, and/orthe worker manager 140. For example, the routing manager 150 may beimplemented entirely within one of the other components of the virtualcompute system 110 or in a distributed manner across the othercomponents of the virtual compute system 110. In the example of FIG. 1,the routing manager 150 includes mapping data 150A. The mapping data150A may include data indicating how the incoming code executionrequests should be routed to the containers running on the virtualcompute system 110. The mapping data 150A may also include anycontainer/routing policies specified by the users or determined by therouting manager 150 for routing the incoming requests received by thevirtual compute system 110. The mapping data 150A may be stored in astorage device internal to the virtual compute system 110 and/or storedin an external storage device (e.g., storage service 108) andperiodically backed up.

The routing manager 150 may include a routing parameter determinationunit for determining a routing parameter associated with a given codeexecution request, and a container lookup unit for determining theappropriate container to be used to handle the given code executionrequest based on the determined routing parameter. An exampleconfiguration of the routing manager 150 is described in greater detailbelow with reference to FIG. 2.

Maintaining Resources Associated with Containers

In some embodiments, containers running on the virtual compute system110 may be associated with container-specific resources such as memory,disk storage, database, etc. that are accessible by any program codeexecuted in the containers. For example, code execution results of aprogram code executed in a container may be cached in local memoryassociated with the container. The cached results may be utilized by thevirtual compute system 110 to facilitate other code execution requestsof the same type (e.g., requests associated with the same program codeand the same set of arguments). In one example, a user may wish toprovide a weather service that allows people to type in zip codes andview the weather information associated with those zip codes. Every timea zip code is entered, a request may be sent to the virtual computesystem 110 to execute a weather information lookup function (e.g., in acontainer created on a virtual machine instance assigned to the user)using the entered zip code. The lookup function may retrieve the weatherinformation from a weather database using the zip code and output theretrieved weather information. The retrieved weather information mayalso be stored in the memory associated with the container, so that anyfuture code execution requests can utilize the stored information. Forexample, if another request having the same zip code is received (e.g.,within a threshold time period), the weather information lookup functionmay simply return the cached result without going to the weatherdatabase, thereby achieving some latency gains. Even if the currentweather information is cached, if the subsequent requests are routed toa different container that cannot access the cached information, thecached information would not be available to the weather informationlookup function and the latency gains could not be achieved.Additionally, or alternatively, the virtual compute system 110 may haveother resources such as memory, disk storage, database, etc. accessibleat the instance level (e.g., accessible by any program code executed onthe particular instance or any containers thereon) and/or at the accountlevel (e.g., accessible by any program code executed on an instanceassociated with the user).

Mapping Between Requests and Specific Containers

In some embodiments, the routing manager 150 processes the incoming codeexecution requests and determines to which containers the requestsshould be routed. For example, when the virtual compute system 110receives a request associated with a given program code for the firsttime, there may be no mapping that routes the request to a specificcontainer running on the virtual compute system 110. Upon receiving sucha request, an instance may be moved from the warming pool 130A to theactive pool 140A and assigned to the user associated with the request.Then, the virtual compute system 110 can create a container on theinstance, load the program code onto the container, and execute theprogram code in the container. Any information generated or obtainedwhile executing the program code may be stored in one or more computingresources associated with the container. The computing resources mayinclude local memory and/or disk storage accessible only by thecontainer. The computing resources may also include a database that ismaintained on the virtual compute system 110 or on an external service(e.g., auxiliary service 106). Upon storing the information generated orobtained while executing the program code in one or more computingresources, the routing manager 150 may update the mapping data 150A sothat future requests that may benefit from utilizing the storedcontainer-specific information would be routed to this specificcontainer.

The routing manager 150 may utilize any known hashing schemes or otherdata structures to update and maintain the mapping data 150A. Forexample, the execution parameters included in the request may be hashedand mapped to the IDs of the containers. The mapping data 150A mayinclude, for each program code execute on the virtual compute system110, a table mapping various combinations of execution parameters tospecific containers. The routing manager 150 may hash one or more of theexecution parameters included in the request to determine a routingparameter, and use the routing parameter to determine a specificcontainer to which the mapping data 150A maps the routing parameter. Forexample, if a first request requests execution of Function Foo witharguments “current temperature” and “90020,” the routing manager 150 mayroute the first request to a first container, and if a second requestrequests execution of Function Foo with arguments “current temperature”and “10012,” the routing manager 150 may route the second request to asecond container. In another example, the requests may specify the nameof the database that the requests are configured to manage or modify. Insuch an example, the database name may serve as the routing parameterthat is mapped to specific containers (e.g., requests associated withdatabase A mapped to container A, requests associated with database Bmapped to containers B, C, and D, requests associated with databases C,D, and E mapped to container E, etc.).

In other embodiments, only a subset of the parameters are considered ingenerating the routing parameter. In such an example, each requestassociated with Function Foo and argument “current temperature” may berouted to the same container, regardless of other argument values. Inyet another example, the mapping data 150A may provide that all requestsassociated with Function Foo are to be routed to a particular container.Although the example of routing to specific containers is used in someembodiments of the present disclosure, the techniques discussed hereinmay be applied to providing mapping data 150A that maps requests toparticular instances, particular frontends, particular geographiclocations, particular worker managers, etc. such that computingresources at the relevant level of granularity (e.g., instance-specificresources, account-specific resources, location-specific resources,etc.) may be utilized by the requests.

The mapping data 150A may be provided by the user, for example, via oneor more UIs, CLIs, APIs, and/or other programmatic interfaces. Thevirtual compute system 110 may provide certain container information tothe user, for example, when containers are created or terminated, sothat the user can provide the mapping data with respect to specificcontainers. In some embodiments, the mapping data 150A may specify thata first group of requests (e.g., requests associated with Function Foo,requests containing a particular parameter specified by the user,requests receiving during certain hours, etc.) should be routed to onecontainer and a second group of requests should be routed to anothercontainer. By providing an indication in the request that the request isto be handled using a specific container and/or by providing a mappingbetween parameter values (e.g., hash values) and specific containers,the user may control which requests are handled using which containers(and thus have access to which container-specific resources) and achievereduced latencies associated with the requests by omitting costlyoperations using the container-specific resources (e.g., data locallystored within the container). The mapping data 150A may provide routingbased on user account (e.g., requests associated with different useraccounts routed to different containers), program code (e.g., requestsassociated with different program codes routed to different containers),time of day (e.g., requests received at different hours, days, months,years, etc. routed to different containers), geographic regions (e.g.,requests associated with different geographic regions routed todifferent containers), function arguments (e.g., requests havingdifferent combinations of parameters or arguments routed to differentcontainers), other request parameters or metadata, etc. In someembodiments, the portion of the mapping data 150A that would cause suchrequests to be routed to this specific container is deleted upon thetermination of the container (e.g., due to lack of use).

Managing Backend Resources

In some embodiments, the routing manager 150 may monitor backendresources utilized in connection with incoming code execution requests.In some cases, third-party or user-owned resources (e.g., disk storage,database, network, etc.) may be used by program codes executed on thevirtual compute system 110, and such resources may not scale as well asthose managed by the virtual compute system 110 (e.g., handle largeburst traffic), thereby creating an impedance mismatch. In such cases,the virtual compute system 110 may allow the users to specify themapping between requests and containers such that the backend resourcesare utilized in a more controlled manner. For example, the mapping data150A may provide that all requests utilizing a first backend resourceshould be routed to a first container, and all requests utilizing asecond backend resource should be routed to any of a group of tencontainers. In such an example, when a program code is being executed inthe first container, the user can be sure that the program code is theonly one accessing or managing the first backend resource and that thefirst backend resource is not overburdened by a large number ofsimultaneous requests.

User Customization of Compute Capacity

In some embodiments, the virtual compute system 110 may allow users tocustomize the instances that are used to handle their requests. Forexample, a user may specify, for example, via one or more UIs, CLIs,APIs, and/or other programmatic interfaces, that a specific version ofthe language runtime (or other software components) is provided on theinstances servicing the code execution requests associated with theuser. In response, the virtual compute system 110 may install thespecified version of the language runtime when a new instance isassigned to the user such that any container created thereon can accessthe installed language runtime. In some embodiments, the routing manager150 may update the mapping data 150A such that requests associated withthe user are routed to one or more containers running on thesecustomized instances so that, after the initial customization (and theassociated latency hit), subsequent containers created on the customizedinstance can take advantage of the customization.

Frontend/Routing Manager Gossiping Routing Information

In some embodiments, the virtual compute system 110 may have multiplefrontends 120 associated with different sets of warming pool managers130 and worker managers 140. In such embodiments, the routing manager150 may communicate with each of the frontends 120 to provide therouting information used to route incoming code execution requests tospecific containers (or instances). In other embodiments, each frontend120 may be associated with a different routing manager 150. In suchembodiments, the frontends 120 and/or the routing managers 150 maygossip information to each other as soon as new routing information(e.g., mapping data 150A) becomes available so that incoming codeexecution requests can be routed to the appropriate containers. Forexample, as soon as one of the frontends 120 or the routing managers 150obtains or determines new mapping information, the mapping informationis shared with all of the frontends 120 or the routing managers 150 onthe virtual compute system 110.

Account-, Instance-, Function-, and Container-Level Resources (11)

In some embodiments, the virtual compute system 110 maintains one ormore computing resources at various levels. For example, the virtualcompute system 110 may maintain one or more account-level resources(e.g., accessible by any code execution associated with the sameaccount), one or more instance-level resources (e.g., accessible by anycode execution on the same instance), one or more function-levelresources (e.g., accessible by any code execution associated with thesame function or program code), one or more container-level resources(e.g., accessible by any code execution in the same container), etc. Thecomputing resources may include memory, disk storage, database, network,or any other resources that may be accessed during code execution.

External Services Controlling Container Lifecycle

In some embodiments, the virtual compute system 110 may allow thirdparty services (e.g., application performance monitoring service,logging service, etc.) to exercise a certain amount of control over thelifecycle of the containers created on the virtual compute system 110.In some cases, these services may have the ability to ingest only at aspecific rate or only a specific kind of data. In such cases, thevirtual compute system 110 may allow these services to control the tempoat which the containers are created and/or terminated, for example, byallowing these services to perform one or more operations before/aftercontainers are created or terminated. In one example, a logging servicemay perform certain logging operations at the end of a container'slifecycle to perform logging and cleanup operations. In another example,an external service may specify that only specific types of requestsshould be sent to the containers managed by the external service. Inresponse, the routing manager 150 may update the mapping data 150A sothat only the specified types of requests are routed to the containersmanaged by the external service.

Container Lifecycle Management

In some embodiments, the routing manager 150 may keep one or morecontainers alive by refraining from terminating them immediately or soonafter code executions in the containers have been completed. Forexample, the routing manager 150 may cause certain containers to be keptalive even if the containers cannot be used to service any existing codeexecution requests. The decision of whether to keep such containersalive may be based on how frequently the requests that would be handledusing the containers are expected to be received by the virtual computesystem 110 and/or how much information has been stored in associationwith such containers in container-specific computing resources. Theprocess of keeping the containers alive beyond their normal schedule isdescribed in greater detail below with reference to FIG. 6.

Information Regarding Future Code Executions

In some embodiments, the routing manager 150 may maintain executioninformation regarding future code executions on the virtual computesystem 110. For example, such information may provide that Function Yshould be executed upon a successful execution of Function X, and thatFunction Z should be executed upon an unsuccessful execution of FunctionX. In such an example, the routing manager 150 may check the executioninformation after each attempted execution of program codes, todetermine the next course of action. In another example, the routingmanager 150 may maintain the execution information in one or morecomputing resources associated with the container in which the programcode is executed, and check the execution information after a requesthas been routed to the container (e.g., just as the routing manager 150would check the cached information to determine whether or how theprogram code should be executed).

Local Timer

In some embodiments, the routing manager 150 may maintain a local timerwithin individual containers. For example, a first container maymaintain a local timer in a computing resource (e.g., memory, diskstorage, etc.) associated with the first container, and any requestrouted to the first container may utilize the local timer for executingcode in the first container. By maintaining a local timer that can beutilized by requests routed to the first container, the routing manager150 eliminates the need to access certain external services (e.g., ascheduling service external to the virtual compute system 110) tomonitor timing information (e.g., the requests can simply utilize thelocal timer), thereby achieving latency gains.

General Architecture of Routing Manager

FIG. 2 depicts a general architecture of a computing system (referencedas routing manager 150) that manages the virtual machine instances inthe virtual compute system 110. The general architecture of the routingmanager 150 depicted in FIG. 2 includes an arrangement of computerhardware and software modules that may be used to implement aspects ofthe present disclosure. The routing manager 150 may include many more(or fewer) elements than those shown in FIG. 2. It is not necessary,however, that all of these generally conventional elements be shown inorder to provide an enabling disclosure. As illustrated, the routingmanager 150 includes a processing unit 190, a network interface 192, acomputer readable medium drive 194, an input/output device interface196, all of which may communicate with one another by way of acommunication bus. The network interface 192 may provide connectivity toone or more networks or computing systems. The processing unit 190 maythus receive information and instructions from other computing systemsor services via the network 104. The processing unit 190 may alsocommunicate to and from memory 180 and further provide outputinformation for an optional display (not shown) via the input/outputdevice interface 196. The input/output device interface 196 may alsoaccept input from an optional input device (not shown).

The memory 180 may contain computer program instructions (grouped asmodules in some embodiments) that the processing unit 190 executes inorder to implement one or more aspects of the present disclosure. Thememory 180 generally includes RAM, ROM and/or other persistent,auxiliary or non-transitory computer-readable media. The memory 180 maystore an operating system 184 that provides computer programinstructions for use by the processing unit 190 in the generaladministration and operation of the routing manager 150. The memory 180may further include computer program instructions and other informationfor implementing aspects of the present disclosure. For example, in oneembodiment, the memory 180 includes a user interface unit 182 thatgenerates user interfaces (and/or instructions therefor) for displayupon a computing device, e.g., via a navigation and/or browsinginterface such as a browser or application installed on the computingdevice. In addition, the memory 180 may include and/or communicate withone or more data repositories (not shown), for example, to access userprogram codes and/or libraries.

In addition to and/or in combination with the user interface unit 182,the memory 180 may include a routing parameter determination unit 186and a container lookup unit 188 that may be executed by the processingunit 190. In one embodiment, the user interface unit 182, routingparameter determination unit 186, and container lookup unit 188individually or collectively implement various aspects of the presentdisclosure, e.g., maintaining routing information for routing requeststo appropriate containers, processing incoming code execution requests,determining routing parameters associated with the requests, identifyingcontainers to be used for handling the requests, etc. as describedfurther below.

The routing parameter determination unit 186 determines a routingparameter associated with a given code execution request. For example,the routing parameter determination unit 186 processes the codeexecution request and extracts a routing parameter included in therequest. Additionally or alternatively, the routing parameterdetermination unit 186 determines a routing parameter based on one ormore of the account associated with the request, the program codeassociated with the request, the execution parameters included in therequest, or other metadata associated with the request, such as the timeof receipt, etc.

The container lookup unit 188 uses the determined routing parameter tolook up the appropriate container to which the request should be routed.Any known hashing and/or lookup schemes may be used to associate routingparameters to specific containers and determine the appropriatecontainer based on the routing parameter.

While the routing parameter determination unit 186 and the containerlookup unit 188 are shown in FIG. 2 as part of the routing manager 150,in other embodiments, all or a portion of the routing parameterdetermination unit 186 and the container lookup unit 188 may beimplemented, as a single unit, separate units, or in a distributedmanner, by other components of the virtual compute system 110 and/oranother computing device. For example, in certain embodiments of thepresent disclosure, another computing device in communication with thevirtual compute system 110 may include several modules or componentsthat operate similarly to the modules and components illustrated as partof the routing manager 150.

Example Routine for Routing Code Execution Requests

Turning now to FIG. 3, a routine 300 implemented by one or morecomponents of the virtual compute system 110 (e.g., the routing manager150) will be described. Although routine 300 is described with regard toimplementation by the routing manager 150, one skilled in the relevantart will appreciate that alternative components may implement routine300 or that one or more of the blocks may be implemented by a differentcomponent or in a distributed manner.

At block 302 of the illustrative routine 300, the routing manager 150maintains a plurality of virtual machine instances. The plurality ofvirtual machine instances may include a warming pool (e.g., warming pool130A) comprising virtual machine instances having one or more softwarecomponents loaded thereon and waiting to be assigned to a user, and anactive pool (e.g., active pool 140A) comprising virtual machineinstances currently assigned to one or more users. The virtual machineinstances in the active pool may have one or more containers createdthereon for executing program codes therein.

At block 304, the routing manager 150 processes a request to execute aprogram code on the virtual compute system 110. The request may includea user indication that that the program code is to be executed based onone or more computing resources modified by a prior execution of theprogram code. For example, a prior execution of the program code mayhave caused certain data (e.g., key-value pairs stored in a database,function return values, etc.) to be retrieved (e.g., from an externaldatabase service in communication with the virtual compute system 110)or calculated and stored locally within the container in which the priorexecution occurred, and any subsequent requests that may benefit fromhaving access to the stored data or any subsequent requests that includeuser indications to use such stored data may be routed to the containerin which the prior execution occurred so that the subsequent executionshave access to the locally stored data. The request may also includeuser account information (e.g., identity of the account associated witha user), program code information (e.g., identity of the first programcode to be executed) and one or more parameters (e.g., executionparameters, function arguments, etc.) to be used for executing the firstprogram code.

At block 306, the routing manager 150 identifies, based on the userindication that that the program code is to be executed based on one ormore computing resources modified by a prior execution of the programcode, a container on a first virtual machine instance of the pluralityof virtual machine instances that is associated with the one or morecomputing resources. For example, the routing manager 150 may calculatea hash value based on the user indication provided in the request, andperform a lookup of the hash value in a mapping table (e.g., mappingdata 150A) maintained on the virtual compute system that maps hashvalues to specific containers. For example, the user indication (or themapping data 150A maintained on the virtual compute system 110) mayfurther provide that requests associated with the same parameters (e.g.,zip code to be used to look up weather information) should be routed tothe same container. Although the container is used as an exampledestination, the request or the mapping data 150A may indicate that therequest should be routed to one of multiple containers or a group ofcontainers.

At block 308, the routing manager 150 causes the program code to beexecuted in the container. In one example, the routing manager 150 (oranother component of the virtual compute system 110 such as the workermanager 140) may determine whether a request of the same type has beenprocessed in the container, and if so, determine whether one or morecomputer resources associated with the container contains informationthat can facilitate the execution of the program code. For example,prior execution results associated with the program code may have beenstored in a memory associated with the container. In such a case, thecurrent execution of the program code may output or return the priorexecution results or omit certain computing operations (e.g., dataretrieval, function invocation, data calculation, etc.) based on theavailability of the prior execution results, thereby achieving a reducedlatency.

While the routine 300 of FIG. 3 has been described above with referenceto blocks 302-308, the embodiments described herein are not limited assuch, and one or more blocks may be omitted, modified, or switchedwithout departing from the spirit of the present disclosure.

Example Mapping Table

Turning now to FIG. 4, an example mapping table maintained either by thevirtual compute system 110 or by an auxiliary service 106 of FIG. 1 willbe described. As illustrated in FIG. 4, the table 400 includes incomingcode execution requests labeled “Request A,” “Request B,” “Request C,”and “Request D,” each of which associated with a routing parameter and acontainer ID. For example, Request A has a routing parameter value of Xand a container ID of 2, Request B has a routing parameter value of Yand a container ID of 7, Request C has a routing parameter value of Cand a container ID of 2, and Request D has a routing parameter value ofD and a container ID of 1. In the example of FIG. 4, it is assumed thatRequests A-D are received by the virtual compute system 110 sequentially(e.g., A, then B, then C, and then D). The routing manager 150 maydetermine the routing parameter associated with Request A, either basedon the routing parameter included in the request or based on the natureof the request (e.g., associated user account, function, etc.). Therouting manager 150 determines the routing parameter of Request A to be“X” and identifies the container associated with the routing parameterX, which is the container having an ID value of 2. After Request A isprocessed, Request B is received and is routed to a container having anID value of 7 based on the determined routing parameter value of “Y.”When Request C is received, the routing manager 150 determines thatRequest C has the same routing parameter value has a previously handledRequest A. According to the mapping table 400, Request C is also handledusing the container having an ID value of 2, potentially achieving somelatency gains if Request C is able to utilize information processed byRequest A and stored in association with the container having the IDvalue of 2. Then, Request D is received and is routed to a containerhaving an ID value of 1 based on the determined routing parameter valueof “Z.” In some embodiments, the routing parameter value may indicatethe specific resources (e.g., resource ID identifying resources such asresources 158C and resources 159A-1 of FIG. 1) requested for executingthe program codes. For example, requests requesting to use the sameresource may be routed to the same container or the same group ofcontainers.

The mapping table (or mapping data 150A) is not limited to theconfiguration shown in the example of FIG. 4, and may include any numberof parameters that can be used for determining how the requests shouldbe routed to which containers.

Example Routine for Caching Code Execution Results

Turning now to FIG. 5, a routine 500 implemented by one or morecomponents of the virtual compute system 110 (e.g., the routing manager150) will be described. Although routine 500 is described with regard toimplementation by the routing manager 150, one skilled in the relevantart will appreciate that alternative components may implement routine500 or that one or more of the blocks may be implemented by a differentcomponent or in a distributed manner.

At block 502 of the illustrative routine 500, the routing manager 150routes a request to execute a program code to a container. The containerto which the request is routed may have been identified according to theroutine 300 described with reference to FIG. 3.

At block 504, the routing manager 150 determines whether a prior codeexecution data that may be utilized by the request is available in oneof the resources (e.g., memory, disk storage, database, etc.) associatedwith the container. In some examples, the routing manager 150 maydetermine whether the computing resources associated with the containercontains any information available for use in connection with thecurrent request (e.g., code execution results, or other data,determinations, and/or calculations). If the routing manager 150determines that a prior code execution data that may be utilized by therequest is available, the routine proceeds to block 510, where the priorcode execution data is presented to the program code. Otherwise, theroutine 500 proceeds to block 506.

At block 506, the routing manager 150 causes the program code to beexecuted in the container. The program code may be executed using one ormore parameters included in the request. In some embodiments, the cacheddata presented to the program code causes the program code to start at adifferent state than the program code would have without the cacheddata. The program code may omit certain computing operations (such asdata retrieval or calculations) based on the availability of the cacheddata. Once the code execution is finished, the routing manager 150 maystore any information that may facilitate the processing of futurerequests of the same or similar type in one or more computing resourcesassociated with the container. At block 508, the routing manager 150outputs the code execution result obtained from executing the programcode. In some cases, the outputted code execution result may beidentical to the cached data presented to the program code at block 510.In other cases, the program code further processes or modifies thecached data to produce a code execution result that is different fromthe cached data.

While the routine 500 of FIG. 5 has been described above with referenceto blocks 502-510, the embodiments described herein are not limited assuch, and one or more blocks may be omitted, modified, or switchedwithout departing from the spirit of the present disclosure.

Example Routine for Managing Container Lifecycle

Turning now to FIG. 6, a routine 600 implemented by one or morecomponents of the virtual compute system 110 (e.g., the routing manager150) will be described. Although routine 600 is described with regard toimplementation by the routing manager 150, one skilled in the relevantart will appreciate that alternative components may implement routine600 or that one or more of the blocks may be implemented by a differentcomponent or in a distributed manner.

At block 602 of the illustrative routine 600, the routing manager 150finishes executing a program code on a container. At block 604, therouting manager 150 updates one or more computing resources associatedwith the container based on the finished execution. The updatedcomputing resources may include information that may facilitate theprocessing of future requests of the same or similar type, as discussedwith reference to FIG. 5.

At block 606, the routing manager 150 determines whether one or morethreshold criteria for keeping a container alive are satisfied. In somecases, a container may not be immediately shut down even if the virtualcompute system 110 does not have any request that can be handled usingthe container, in anticipation that such a request may shortly arriveand utilize the information stored in association with the container. Insuch cases, if the performance gain achieved by keeping the containeralive and handling a future request using the container outweighs thecost of keeping the container alive, the routing manager 150 may chooseto keep the container alive for an extended period of time beyond thenormal schedule. The threshold criteria may include a thresholdfrequency level at which requests of the same type are received. Forexample, if a container has cached information that can be utilized by alarge number in the near future (e.g., expected to be received at agreater frequency than the threshold frequency level), the routingmanager 150 may keep the container alive. The threshold criteria mayinclude a threshold size of the information stored in association withthe container. If the container has a lot of information (e.g., greaterthan the threshold amount) stored in a local memory or storage, therouting manager 150 may keep the container alive. If the routing manager150 determines that the threshold criteria are not satisfied, theroutine 600 proceeds to 610. Otherwise, the routine 600 proceeds toblock 608.

At block 608, the routing manager 150 keeps the container running forhandling future code execution requests. In some embodiments, theduration for which the containers are kept alive beyond their normalschedule is proportional to the size of the information stored in thecontainers or the frequency at which requests that would use theinformation stored in the containers are expected to be received. Inother embodiments, the containers are kept alive for a fixed duration,and if the containers remain idle for the fixed duration, the containersare shut down.

At block 610, the routing manager 150 causes any cached data associatedwith the container to be presented to a shutdown program code (orshutdown hook) configured execute when the container is shut down. Theshutdown program code may be used to perform any logging, monitoring,cleanup, or other operations associated with the container. At block612, the routing manager 150 causes the shutdown program code to beexecuted in the container. At block 614, the routing manager 150 causesthe container to be shut down. In some embodiments, the routing manager150 may notify the container of the shutdown before the shutdown isperformed, so that any data stored in the container-specific computingresources can be stored in permanent storage available even aftershutting down the container.

While the routine 600 of FIG. 6 has been described above with referenceto blocks 602-608, the embodiments described herein are not limited assuch, and one or more blocks may be omitted, modified, or switchedwithout departing from the spirit of the present disclosure. Forexample, in some embodiments, at block 614, the container is not shutdown but instead reset or cleared.

OTHER CONSIDERATIONS

It will be appreciated by those skilled in the art and others that allof the functions described in this disclosure may be embodied insoftware executed by one or more physical processors of the disclosedcomponents and mobile communication devices. The software may bepersistently stored in any type of non-volatile storage.

Conditional language, such as, among others, “can,” “could,” “might,” or“may,” unless specifically stated otherwise, or otherwise understoodwithin the context as used, is generally intended to convey that certainembodiments include, while other embodiments do not include, certainfeatures, elements and/or steps. Thus, such conditional language is notgenerally intended to imply that features, elements and/or steps are inany way required for one or more embodiments or that one or moreembodiments necessarily include logic for deciding, with or without userinput or prompting, whether these features, elements and/or steps areincluded or are to be performed in any particular embodiment.

Any process descriptions, elements, or blocks in the flow diagramsdescribed herein and/or depicted in the attached figures should beunderstood as potentially representing modules, segments, or portions ofcode which include one or more executable instructions for implementingspecific logical functions or steps in the process. Alternateimplementations are included within the scope of the embodimentsdescribed herein in which elements or functions may be deleted, executedout of order from that shown or discussed, including substantiallyconcurrently or in reverse order, depending on the functionalityinvolved, as would be understood by those skilled in the art. It willfurther be appreciated that the data and/or components described abovemay be stored on a computer-readable medium and loaded into memory ofthe computing device using a drive mechanism associated with a computerreadable storage medium storing the computer executable components suchas a CD-ROM, DVD-ROM, or network interface. Further, the componentand/or data can be included in a single device or distributed in anymanner. Accordingly, general purpose computing devices may be configuredto implement the processes, algorithms, and methodology of the presentdisclosure with the processing and/or execution of the various dataand/or components described above.

It should be emphasized that many variations and modifications may bemade to the above-described embodiments, the elements of which are to beunderstood as being among other acceptable examples. All suchmodifications and variations are intended to be included herein withinthe scope of this disclosure and protected by the following claims.

What is claimed is:
 1. A system for providing low-latency computationalcapacity, the system comprising: an external database service configuredto store a plurality of key-value pairs; a virtual compute systemcomprising one or more hardware computing devices executing specificcomputer-executable instructions, the virtual compute system incommunication with the external database service and configured to atleast: maintain a plurality of virtual machine instances on one or morephysical computing devices, wherein the plurality of virtual machineinstances comprises: a warming pool comprising virtual machine instanceshaving one or more software components loaded thereon and waiting to beassigned to a user; and an active pool comprising virtual machineinstances currently assigned to one or more users; process a firstrequest to execute a first program code associated with a first user onthe virtual compute system, the first request including an identity ofthe first user, and one or more first execution parameters to be usedfor executing the first program code; execute the first program code ina first container created on a first virtual machine instance in theactive pool using the one or more first execution parameters, theexecution of the program code causing one or more key-value pairs of theplurality of key-value pairs to be retrieved from the external databaseservice and stored locally within the first container; process a secondrequest to execute the first program code on the virtual compute system,the second request including the identity of the first user, one or moresecond execution parameters to be used for executing the first programcode, and a user indication that the second request is to be handledusing the first container previously used for handling the firstrequest; and based on the user indication that the second request is tobe handled using the first container, execute the first program code inthe first container using the one or more second execution parameters,the execution of the first program code accessing the one or morekey-value pairs locally stored within the first container such that alatency associated with the execution of the first program code based onthe one or more second execution parameters is reduced.
 2. The system ofclaim 1, wherein the virtual compute system is configured to identifythe first container by calculating a hash value associated with the userindication and performing a lookup of the calculated hash value in amapping table maintained by the virtual compute system, the mappingtable mapping one or more hash values to specific containers running onthe plurality of virtual machine instances.
 3. The system of claim 1,wherein the execution of the first program code using the one or moresecond execution parameters omits at least one retrieval of data fromthe external database service based on the one or more key-value pairslocally stored within the first container.
 4. The system of claim 1,wherein the virtual compute system is further configured to keep thefirst container running even after the execution of the first programcode using the one or more second execution parameters has beencompleted such that subsequent requests providing indications to use thefirst container can be handled using the first container.
 5. A systemcomprising: a virtual compute system comprising one or more hardwarecomputing devices executing specific computer-executable instructionsand configured to at least: maintain a plurality of virtual machineinstances on one or more physical computing devices; process a firstrequest to execute a first program code on the virtual compute system,the first request including user account information, one or moreparameters to be used for executing the first program code, and a userindication that the first program code is to be executed based on one ormore computing resources modified by a prior execution of the firstprogram code; based on the user indication that the first program codeis to be executed based on one or more computing resources modified by aprior execution of the first program code, identify a first container ona first virtual machine instance of the plurality of virtual machineinstances that is associated with the one or more computing resourcesmodified by a prior execution of the first program code; and cause thefirst program code to be executed in the first container based on theone or more computing resources associated with the first container. 6.The system of claim 5, wherein the virtual compute system is configuredto maintain a mapping table that maps one or more values associated withincoming code execution requests to specific containers running on theplurality of virtual machine instances.
 7. The system of claim 5,wherein the one or more computing resources associated with the firstcontainer comprise local storage within the first container storing dataretrieved, in connection with the prior execution of the first programcode, from an external service that is in communication with the virtualcompute system.
 8. The system of claim 5, wherein the virtual computesystem is further configured to: determine that the one or morecomputing resources associated with the first container contains cacheddata associated with the prior execution of the first program code; andcause the cached data to be presented to the execution of the firstprogram code in the first container, wherein the execution of the firstprogram code omits at least one computing operation based on the cacheddata, thereby achieving a reduced latency.
 9. The system of claim 5,wherein the first virtual machine instance has one or moreinstance-specific computing resources that are accessible by one or morecontainers running on the first virtual machine instance.
 10. The systemof claim 5, wherein the user indication specifies a parameter thatcauses the virtual compute system to route the first request to acontainer of a user's choice.
 11. The system of claim 5, wherein thevirtual compute system is configured to route incoming code executionrequests including the same user indication to the same container. 12.The system of claim 5, wherein the virtual compute system is furtherconfigured to automatically execute a shutdown program code associatedwith the first container when the first container is shut down.
 13. Acomputer-implemented method comprising: as implemented by one or morecomputing devices configured with specific executable instructions,maintaining a plurality of virtual machine instances on one or morephysical computing devices; processing a first request to execute afirst program code on the virtual compute system, the first requestincluding user account information, one or more parameters to be usedfor executing the first program code, and a user indication that thefirst program code is to be executed based on one or more computingresources modified by a prior execution of the first program code; basedon the user indication that the first program code is to be executedbased on one or more computing resources modified by a prior executionof the first program code, identifying a first container on a firstvirtual machine instance of the plurality of virtual machine instancesthat is associated with the one or more computing resources modified bya prior execution of the first program code; and causing the firstprogram code to be executed in the first container based on the one ormore computing resources associated with the first container.
 14. Themethod of claim 13, further comprising maintaining a mapping table thatmaps one or more values associated with the incoming code executionrequests to specific containers running on the plurality of virtualmachine instances.
 15. The method of claim 13, wherein the one or morecomputing resources associated with the first container comprise localstorage within the first container storing data retrieved, in connectionwith the prior execution of the first program code, from an externalservice that is in communication with the virtual compute system. 16.The method of claim 13, further comprising: determining that the one ormore computing resources associated with the first container containscached data associated with the prior execution of the first programcode; and causing the cached data to be presented to the execution ofthe first program code in the first container, wherein the execution ofthe first program code omits at least one computing operation based onthe cached data, thereby achieving a reduced latency.
 17. The method ofclaim 13, wherein the first virtual machine instance has one or moreinstance-specific computing resources that are accessible by one or morecontainers running on the first virtual machine instance.
 18. The methodof claim 13, wherein the user indication specifies a parameter thatcauses the virtual compute system to route the first request to acontainer of a user's choice.
 19. The method of claim 13, furthercomprising routing incoming code execution requests including the sameuser indication to the same container.
 20. The method of claim 13,further comprising automatically executing a shutdown program codeassociated with the first container when the first container is shutdown.